Wireless communications devices, such as cellular telephones, may have a wide variety of accessories. Examples of accessories include battery packs, hands-free operation adapters, plug-in memory cartridges, and so forth. These various accessories, when connected to the wireless communications device, expand the device's capabilities.
When using the accessories, there is a great need to identify which type of accessory is being used so that operation may be optimized. For instance, the variety of rechargeable batteries for portable wireless communications devices have increased over time and continues to grow. Numerous different battery cell chemistries have been employed such as Lithium, Nickel Cadmium (NiCd), Nickel Metal Hydride (NiMH), and Alkaline. These battery cells are typically assembled into battery packs having various numbers of cells and overall capacities. Different battery pack types typically have different charge capacities and optimum charging profiles. Attempting to recharge a battery pack using a different profile may not only diminish battery life and efficiency, but may also create a hazard due to overcharging and overheating. As such, it is desirable for a battery charger, internal or external to a wireless communications device, to know which type of battery pack is being recharged.
Further, different battery packs exhibit different end of life voltage and other operational characteristics. As such, knowledge of the type of battery pack may be useful to wireless communications devices in regulating operational parameters such as transmitter output power or in warning the user of a "low battery" condition.
Thus, there remains a need for an inexpensive apparatus and method to automatically determine the type or class of battery pack so that charging or operational characteristics may be optimized. Preferably, the battery charger automatically recognizes the battery pack type being charged and adapts its charging and/or operational parameters accordingly.